Conformational changes and dynamic rheological properties of fish sarcoplasmic proteins treated at various pHs

Panchaporn Tadpitchayangkoon, Jae W. Park, Jirawat Yongsawatdigul

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

The conformational changes and rheological properties of soluble sarcoplasmic proteins isolated from striped catfish (Pangasius hypophthalmus), treated at various pHs (2-12), were investigated. Isoelectric point of striped catfish sarcoplasmic proteins was determined to be pH 5. SDS-PAGE of sarcoplasmic proteins treated at various pHs, showed molecular masses ranging from 11 to 97 kDa. Most sarcoplasmic proteins, regardless of treated pHs, showed a molecular mass of 43 kDa. A decrease in total sulfhydryl content was observed when the pH was shifted away from 6, indicating disulfide formation at pH lower and higher than 6. Gradual increases of S 0-ANS and S 0-PRODAN were observed as pH increased from 6 to 12, indicating the unfolding of sarcoplasmic proteins during alkaline extraction. DSC thermograms of sarcoplasmic proteins treated at pH 5-9 exhibited an exothermic transition peak, probably due to disulfide bond formation, and/or hydrophobic interactions, which was highly related to the onset temperature of G′ rising. Gel network formation of sarcoplasmic proteins did not take place at extreme pHs (<4 or >9) where proteins were highly charged while the viscoelastic properties of sarcoplasmic proteins were observed at pH 5.5-9. The highest G′ value at 90 °C was observed at pH 5.5 and 8 (P ≤ 0.05). The gel point, a temperature at which G′ = G″, increased to higher temperature as pH was shifted away from 7.

Original languageEnglish
Pages (from-to)1046-1052
Number of pages7
JournalFood Chemistry
Volume121
Issue number4
DOIs
Publication statusPublished - 2010 Aug 15
Externally publishedYes

Fingerprint

Fish Proteins
rheological properties
Fish
fish
Proteins
proteins
Pangasianodon hypophthalmus
Catfishes
Molecular mass
Disulfides
Temperature
Gels
Protein Unfolding
Isoelectric Point
Hydrophobic and Hydrophilic Interactions
gels
molecular weight
Polyacrylamide Gel Electrophoresis
temperature
hydrophobic bonding

ASJC Scopus subject areas

  • Food Science
  • Analytical Chemistry

Cite this

Conformational changes and dynamic rheological properties of fish sarcoplasmic proteins treated at various pHs. / Tadpitchayangkoon, Panchaporn; Park, Jae W.; Yongsawatdigul, Jirawat.

In: Food Chemistry, Vol. 121, No. 4, 15.08.2010, p. 1046-1052.

Research output: Contribution to journalArticle

Tadpitchayangkoon, Panchaporn ; Park, Jae W. ; Yongsawatdigul, Jirawat. / Conformational changes and dynamic rheological properties of fish sarcoplasmic proteins treated at various pHs. In: Food Chemistry. 2010 ; Vol. 121, No. 4. pp. 1046-1052.
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